It is well known in the art that magnetic inspection particle systems are useful and important in industrial applications. The basic application of this system is for non-destructive testing of an item. This importance is clearly set forth in U.S. Pat. No. 4,812,249 relating to a test system by Isabelle Y. Duminy-Kovarik, incorporated herein by reference.
A major problem with the magnetic inspection particle system is a testing of the materials and particles themselves for their effectiveness. This test for effectiveness is critical. As parts are inserted into the suspension, and tested, the testing suspension of particles will lose some of its effectiveness. It is very critical to have the suspension be effective and be able to easily determine the effectiveness of that suspension by a simple test, in order to have each part tested efficiently.
A suspension for the purposes herein is deemed to include wet method materials borne in conditioned water or kerosene-type liquid, and dry-method materials applied directly to the test surface.
This action is critical because of the expensive nature of the suspension, and the expensive parts which are being tested. It is hypercritical that these parts be tested efficiently and effectively with an effective suspension. If such efficient or effective testing is not achieved, or if the suspension is not known to have failed or been found deficient in its effectiveness, a detective part may receive a false approval and be used in a dangerously unsuitable manner. This defective part can eventually lead to a failure of a system in which it is used.
In order to compensate for this depletion of the magnetic inspection particle fluid during a series of tests on various parts, it is known to use a piece or part with a known crack in it for testing purposes. This process or testing mechanism is difficult to reproduce from factory to factory or establishment to establishment because no two cracks are the same. Thus, a part with a predetermined crack may not be the same as a part with predetermined crack in another location. In this fashion, it is impossible to use this test to have an accurately reproducible test at various locations.
There is also a settling tube or bulb test. However, the settling tube test merely shows the number of particles in the suspension. It does not show the effectiveness of the particles or the brightness of the particles or the sensitivity of the particles. The settling bulb test merely shows the number of particles in the suspension. A repeatedly used fluid can lose brightness and sensitivity. The settling bulb test is also effected by dirt, scale and metal particles from the part itself being tested. The settling bulb test thus suffers from a number of inaccuracies, especially regarding actual particle performance.
Another test for use a magnetic inspection particle fluid is a ring test. This device is accomplished by a ketos ring or Tiede MTU#3 ring. These rings suffer from a similar problem in that the ring itself is not consistently reproducible. This factor greatly interferes with the desirability of providing the same test to the same fluid at a number of different sites.